This section is from the book "Sub-Alpine Plants Or Flowers Of The Swiss Woods And Meadows", by H. Stuart Thompson. Also available from Amazon: Sub-Alpine Plants: Or, Flowers of the Swiss Woods and Meadows.
Annual. Quite glabrous and very small. Leaves slender, linear or sometimes cylindrical, green. Flowers in elongated cymes, yellow. Sepals obtuse.
Dry, stony places and rocks of primary formation up to 8200 feet. July, August.
Nearly all Europe, Western Asia, Greenland. Sedum roseum Scop. (Rhodiola rosea L.). Rose-root.
Robust, 6-12 inches high. Rootstock tuberous and thick, with scent of roses. Buds scaly. Stem simple, erect, very leafy. Leaves ovate-elliptical, serrate towards the apex, densely crowded. Flowers small, greenish yellow or reddish, unisexual and dioecious.
Primary rocks, 4000-8000 feet; local. July, August.
Central and Northern Europe, Siberia, Himalaya, N.America. British. Canadian Rockies, 7000 feet. (E. Whymper).
Robust fleshy herbs, with perfect flowers in panicled or corymbose cymes. Petals and calyx-teeth 6 or more, the petals being distinct or connate. Stamens generally twice as many as petals. Carpels free or connate, adnate to calyx-tube, many-seeded.
About 50 species, inhabiting Europe, Asia, and Africa.
Rosettes large, and whole plant robust and often a foot or more high. Rosette leaves suddenly narrowed into a mucro; stem-leaves broadly linear, spreading. Petals lanceolate or linear, twice as long as calyx-teeth, pink.
Rocks, especially limestone, up to 8200 feet. June to August.
Europe, especially central; Caucasus, Persia.
Naturalised in Britain, and generally in Europe, except in the Alps. It was formerly planted on roofs and walls as a supposed protection against lightning.
Rosettes with lanceolate or obovate leaves, abruptly acute, covered with short glandular hairs, stiffly ciliated, bearded at the apex, with radiating, spider's web-like hairs, uniting the ends of the leaves. Petals narrowly lanceolate, acuminate, 3 times as long as the calyx, rose-red, sometimes with a darker streak. The stem and stem-leaves often reddish.
Rocks of the Alps and sub-Alps, 4000-9500 feet; widely spread but local, and much rarer on limestone than siliceous rock, e.g. it has not been recorded from the whole range of the Jura, where its place is taken on the Reculet, etc., by a somewhat similar species, S. Fau-conneti Reuter, intermediate (though not a hybrid) between this and S. montanum.
S. arachnoideum sometimes covers the rocks in immense masses, and the rosettes are often quite white with 'spiders' webs.'
Carpathians, Eastern, Central, and Western Alps, Pyrenees, Central Plateau of France, Cevennes, Corbieres, Apennines.
Rosettes with lanceolate - wedge - shaped, shortly acuminate leaves, glandular-villous on both sides, obscurely ciliated with longish hairs. Stem-leaves lanceolate, somewhat broader towards apex. Petals lanceolate-subulate, very acute, 3 or 4 times as long as the calyx, deep lilac, with a darker streak.
A taller and more robust plant than the last, and less common, though widely spread on primary rocks, and especially on the isolated blocks of rock called 'Befen.' It reaches 9600 feet, and rarely descends into the valleys.
Carpathians, Eastern, Central, and Western Alps, Pyrenees, Corsica.
Sempervivums are most attractive plants for walls and rockeries, and they are readily increased by division of the offshoots. They are all of very easy culture in any light soil in hot aspects, and may be grown on almost any kind of rock. They can be attached to rock by means of fairly moist clay and the plant dibbled in, and they will soon grow and make a good clump.